The Traffic Accident Reconstruction Origin -Editorial-

What is a Accident Reconstruction Engineer? Rusty Haight

While browsing through the TARO site, on the AR news page under the heading "Who can Contribute" TARO has listed "police officers" and "accident reconstruction engineers" as contributors. This is a sore spot with me (see SAE paper 940153 "Qualifications of the Reconstructionist: Differing Points of View" and SOAR Journal "What ARE the qualifications of an Accident Reconstructionist?").

I take the position that Accident Reconstructionists are neither "police officers" nor "engineers" in the traditional sense of either profession. A Reconstructionist needs some of the abilities and attributes of a police officer and some of the engineer or scientist.

For example, most engineering backgrounds have solid math and physics backgrounds but their pursuit of a traditional engineering degree does not include much if any information on the application of those underlying sciences to motor vehicle collisions. The typical Physics 101 course covers friction topics and may well touch on cars skidding to a stop in general terms but does not address the many different aspects of cars braking, skidding, sideslipping, the effect of ABS or the failure of a brake at one or more wheels. I have a physics text which devotes all of 3 paragraphs to the topic of friction using a skidding car as an example but nothing about identifying the tire marks or how those marks may have been made.

On the other hand, the typical accident investigation class offered by, for example, School "X" does little to address the underlying physics, but goes to great lengths to address how a tire mark may have been made and why the tire mark looks the way it does - what was the car doing to make the mark as it appears.

So, the student at School "X" course is shorted on the underlying physics and the engineer is shorted on the application of the underlying physics. Neither, by themselves is a "whole" reconstructionist.

At the Texas Engineering Extension Service (TEEX), we've taken the position that, in training a "reconstructionist" we have to balance the underlying applicable sciences with the application specific information. We go into the underlying science (we were the first to offer a comprehensive Applied Physics class some 3 years ago while IPTM just recently started offering theirs) and mate it with the application specific information necessary to use the science correctly.

Where this is leading is that there are those who will visit the TARO site who will take offense to a category being listed simple as "police officers" and another listed with the artificially elevated title of "accident reconstruction engineers." Consider this: there is not one state that I've found that licenses a professional engineer as an "accident reconstruction engineer" or uses that title in the name of any of their branch licenses for Professional Engineers. The Accreditation Board for Engineering and Technology (a national board that accredits college and university degree programs) does not accredit any degree path in accident reconstruction. Elevating the title to one similar to "Civil Engineer" or "Licensed Consulting Engineer" is, I think, most inappropriate.

One of my favorite examples of (a) a failure of the common sense lobe of the brain or (b) a failure of the individual's training somewhere along the line comes from an exam I was involved in which stems from a crash test I was involved in creating. This crash was an in-line rearender, car "A" rearends car "B". One of the questions posed the candidate was, how fast was each car going. From both a police officer and a Ph.D. engineer we got answers that had car B (the struck car) going faster than car A. Curious, no? Isolated example? NO!

Another of my pet stories involves the man with the Ph.D. now doing reconstruction. He uses a lady's running shoe filled with concrete as a drag sled....now, isn't that just...well, special? He can argue that friction is friction is friction and, on that basis be right, but I suspect that static friction and sliding or dynamic friction for a shoe and a Pirelli P6 radial may not be exactly the same all the time...

My last pet engineer/cop story goes to the very heart of understanding the application of what one learns in the traditional engineering school. Seems a now retired reconstructionist held in high esteem by many of us in this business was working a case back in the deep south. He had the original investigating officer out at the scene of a terrible wreck some months after it had occurred. The original investigating officer - a "police officer", not to be confused with an "accident investigator" or "reconstructionist" - took no measurements or photos of the scene. The consultant reconstructionist was asking him to estimate where he found certain things in the road. The officer pointed to where he said this was and the consultant marked the area with chalk "X". The consultant asked where that was, and the police officer obliged by pointing again. The consultant marked that point with another "X". Then the consultant got out his roll-a-meter wheel and started to measure where these general, roughly estimated, approximations were on the road. An engineer there with the consultant also working on the case called out in a panic "hey, is that roll-a-meter calibrated?" The venerable old consultant stopped short and said, "why no, it's not." But, on the other hand, it's no more or less calibrated than the guesstimates the officer had made for them to that point... The engineer, interested in precision, had forgotten his lecture on significant figures. The "Reconstructionist" - a man with a background both in the underlying sciences and police common sense and investigative ability understood the limitations of the information he was working with. He knew how to judiciously apply it.

In short, just being a cop (or former cop), or just having a degree in a branch of engineering no matter how remotely related to the road or vehicles just isn't enough. There's no degree specifically in "reconstruction" and the best we have are the accident-specific courses offered by Northwestern, IPTM and TEEX to tie what we learn in Physics 101, Dynamics and maybe Mechanics together with what we learn on the street as accident investigator police officers.

My suggestion would be to change the description of "who can contribute" to something along this line:

• Practicing accident reconstructionists of various backgrounds including police accident investigation assignments, engineering specialties, forensic studies and academics regularly visit the TARO site and contribute to the AR News thread. You may expect responses from people with specialty training in a particular area as well as those simply adding little more than anecdotal information to your original question or comment.

Rusty Haight is currently a staff instructor at Texas Engineering Extension Service at Texas A&M University. Leaving police work in 1984, he's since been involved in more than 360 crash tests - driving in some 220 of those including a car-to-car collision at 39 mph with a measured delta-V of 20 mph. He is a founding representative to the ACTAR Board of Directors. He also maintains a private reconstruction practice. He can be reached at [email protected] or [email protected]